Gravity and agriculture

Hi "Dr Omni",

I understand this is one of the things they plan to test in the ISS. A
14 day Shuttle mission is no use for the purpose, and while I believe
some experiments were carried out on MIR, I must admit I'm not sure of
the results. Plant growth experiments were carried out on Earth using
Lunar soil, and I gather they grew 6 times better in that than in Earth
soil, but this doesn't tell us anything much about gravitational
effects.

Best wishes, Andy.

"Dr. Omni" wrote:

> Hi all,
>
> Does someone know how well plants go on micro-gravity environments? I
> know
> that some experiments with plant growth were conducted in the space
> shuttle
> in the eighties, but I know nothing about the results. My gut feeling
> is
> that geotropism - the tendency of plants to grow upright, in order to
> sustain their structure against gravity - would be completely screwed
> up,
> but otherwise they would be somewhat normal in terms of nutrient and
> seed
> production. (Vegetables in general are pretty amorphous organisms,
> when
> compared to animals, and I think that the chance of things going awry
> in the
> development of a plant in zero-g are correspondingly small.)
>
> If that assumption is correct, then agricultural sectors in space
> colonies
> could have a fairly small gravity (just enough to keep water in the
> hydroponic tanks, and that sort of thing) thus minimizing structural
> costs.
> In fact, for the case of a colony associated with an asteroid, the
> agricultural sector could indeed be completely detached from the
> colony: it
> could be a transparent pressure bubble built around the asteroid, with
>
> plants growing close to its surface; the bubble could rotate in a
> 24-hour
> cycle (regardless of the asteroid rotation) and be filled with nearly
> pure
> C02. (One could argue that the gravity of an asteroid wouldn't be
> sufficient
> even for keeping "water in the hydroponic tanks, ad that sort of
> thing".
> Well, I don't have a final answer on that - experimentation only could
> give
> it - but observations made on the surface of Eros show that boulders
> have
> rolled to the bottom of the depressions of the asteroid even with its
> nearly
> zero gravity. That is not so outlandish as it may seem at first: with
> 0.001
> g, like in Eros, you would be able to actually *see* a stone falling
> after
> releasing it - in the first second, it would be half centimetre far
> from
> your hand, and then two centimetres in the next second, and so on...
> You
> would have *clues* that things have some weight there.)
>
> Lucio Coelho
>
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